diff --git a/Gemfile b/Gemfile
index 8a67626c..8376a43e 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,10 +2,10 @@ source 'http://rubygems.org'
 
 gem 'xml-simple'
 gem 'pdfkit'
-gem 'rack', '~>1.3.0'
+gem 'rack', '~>3.1.8'
 gem 'rack-rewrite', '~> 1.2.1'
 gem 'nokogiri', '1.5.10'
-gem 'sinatra', '~>1.3.0'
+gem 'sinatra', '~>4.0.0'
 gem 'rdiscount', '1.6.8'
 gem 'rest-client', '~>1.6.0'
 gem 'json'
diff --git a/Gemfile.lock b/Gemfile.lock
index ea572582..db411c7d 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -5,6 +5,7 @@ GEM
     anemone (0.7.2)
       nokogiri (>= 1.3.0)
       robotex (>= 1.0.0)
+    base64 (0.2.0)
     coderay (0.9.8)
     colorize (0.5.8)
     excon (0.43.0)
@@ -35,16 +36,21 @@ GEM
     mime-types (1.25.1)
     multi_json (1.8.4)
     multipart-post (2.0.0)
+    mustermann (3.0.3)
+      ruby2_keywords (~> 0.0.1)
     netrc (0.7.9)
     nokogiri (1.5.10)
     pdfkit (0.6.2)
-    rack (1.3.10)
+    rack (3.1.8)
     rack-codehighlighter (0.5.0)
       nokogiri (>= 1.4.1)
       rack (>= 1.0.0)
-    rack-protection (1.5.3)
-      rack
+    rack-protection (4.0.0)
+      base64 (>= 0.1.0)
+      rack (>= 3.0.0, < 4)
     rack-rewrite (1.2.1)
+    rack-session (2.0.0)
+      rack (>= 3.0.0)
     rake (0.9.2.2)
     rdiscount (1.6.8)
     rdoc (4.2.0)
@@ -53,14 +59,17 @@ GEM
       mime-types (~> 1.16)
       rdoc (>= 2.4.2)
     robotex (1.0.0)
+    ruby2_keywords (0.0.5)
     rubyzip (1.1.6)
     shotgun (0.9)
       rack (>= 1.0)
-    sinatra (1.3.3)
-      rack (~> 1.3, >= 1.3.6)
-      rack-protection (~> 1.2)
-      tilt (~> 1.3, >= 1.3.3)
-    tilt (1.4.1)
+    sinatra (4.0.0)
+      mustermann (~> 3.0)
+      rack (>= 3.0.0, < 4)
+      rack-protection (= 4.0.0)
+      rack-session (>= 2.0.0, < 3)
+      tilt (~> 2.0)
+    tilt (2.4.0)
     trollop (2.1.1)
     xml-simple (1.1.4)
     yajl-ruby (1.2.1)
@@ -76,12 +85,12 @@ DEPENDENCIES
   link-checker (~> 0.7.2)
   nokogiri (= 1.5.10)
   pdfkit
-  rack (~> 1.3.0)
+  rack (~> 3.1.8)
   rack-codehighlighter
   rack-rewrite (~> 1.2.1)
   rake (~> 0.9.2.2)
   rdiscount (= 1.6.8)
   rest-client (~> 1.6.0)
   shotgun
-  sinatra (~> 1.3.0)
+  sinatra (~> 4.0.0)
   xml-simple